This invention relates to a vehicle power seat switch for adjusting the position of a vehicle seat in the longitudinal direction of a vehicle and in other directions.
A vehicle power seat switch for adjusting the positions of a bottom portion and a back portion of a vehicle seat, e.g., the one disclosed in Japanese Utility Model Publication HEI 1-17057, has been proposed. FIG. 10 is a front view of a vehicle power seat switch of this kind, FIG. 11 is a cross-sectional view of the power seat switch shown in FIG. 10, FIG. 12 is a side view of the power seat switch of FIG. 10, FIG. 13 is a side view of a vehicle seat provided with the power seat switch of FIG. 10, FIG. 14 is a diagram of a reverse side of a knob of the power seat switch of FIG. 10, FIG. 15 is a cross-sectional view taken along the line 15--15 of FIG. 14, and FIG. 16 is a cross-sectional view taken along the line 16--16 of FIG. 14.
In general, a vehicle seat has a seat bottom 31 and a seat back 32, as shown in FIG. 13. A conventional vehicle power switch provided for such a vehicle seat is composed of, as shown in FIG. 10, a switch body 33 attached in the vicinity of the seat bottom 31, a knob 34 for adjusting the seat bottom 31 in the longitudinal direction of the vehicle and in the vertical direction, and another knob 35 disposed above the knob 34 and operated to adjust the tilt position of the seat back 32.
On the switch body 33 are provided projecting shafts 36 to 40 arranged in a horizontal direction and engaged with the knob 34, and projecting shafts 41 and 42 arranged in the vertical direction and engaged with the knob 35, as shown in FIG. 11. Of the projecting shafts 36 to 40, the shafts 36 and 40 located at opposite end positions have circular cross sections and disposed vertically movably, the projecting shaft 38 at the center has a circular cross section and disposed horizontally movably. The other projecting shafts 37 and 39 have generally square cross sections and are fixed to the switch body 33. The upper projecting shafts 41 and 42 respectively have circular cross sections, and the projecting shaft 41 is disposed horizontally movably while the projecting shaft 42 is fixed to the switch body 33.
The lower knob 34 is formed of an elastic synthetic resin, and has upper and lower wall portions 51 and 52 which face each other with the projecting shaft 36 interposed therebetween, guide projections 53a to 53d disposed outside the four corners of the projecting shaft 37, side wall portions 54 and 55 which face each other with the projecting shaft 38 interposed therebetween, guide projections 56a to 56d disposed outside the four corners of the projecting shaft 39, and upper and lower wall portions 57 and 58 which face each other with the projecting shaft 40 interposed therebetween. The upper knob 35 is also formed of an elastic synthetic resin, and has side wall portions 59 and 60 which face each other with the projecting shaft 41 interposed therebetween, and wall portions 61 and 62 positioned around the projecting shaft 42. As shown in FIG. 12, a pair of circular-arc projections 40a and 40b are formed on upper and lower portions of the outside surface of the projecting shaft 40 along the circumferential direction thereof. Similar projections are also provided on the projecting shaft 36. A circular-arc projection 41a is also formed on a side portion of the outside surface of the projecting shaft 41 along the circumferential direction thereof, and another projection (not shown) is formed in the same manner on an opposite portions of the surface of this shaft. Similar projections are also formed on the projecting shafts 38 and 41.
As shown in FIG. 15, a groove 54a for engagement with the corresponding one of the projections of the projecting shaft 38 is formed in the wall portion 54, and a groove 55a is also formed in the wall portion 55 facing the wall portion 54. Similar grooves are also formed in the wall portions 59, 60, 61, and 62. As shown in FIG. 16, grooves 57a and 58a for engagement with the projections 40a and 40b of the projecting shaft 40 are formed in the wall portions 57 and 58, and similar grooves are also formed in the wall portions 51 and 52.
A predetermined gap is provided between the projection 40a and the groove 57a and between the projection 40b and the groove 58a, so that the projecting shaft 40 is movable relative to the knob 34 to the left or right as viewed in FIG. 10. Similarly, a predetermined gap is provided between one of the projections of the projecting shaft 38 and the groove 54a and between the other projection of the projecting shaft 38 and the groove 55a, so that the projecting shaft 38 is movable relative to the knob 34 in the vertical direction. Also, a predetermined gap is provided between one of the projections of the projecting shaft 36 and the groove 51a and between the other projection of the projecting shaft 36 and the groove 52a, so that the projecting shaft 36 is movable relative to the knob 34 to the left or right as viewed in FIG. 10. If each of these gaps is smaller than the predetermined size, the slide resistance of the projecting shafts 36, 38, and 40 is so large that there is a risk of occurrence of return failure after the knob 34 has been moved. The risk of knob 34 return failure is particularly high if the gap is further reduced with a change in the atmospheric temperature.
When the knob 34 of this vehicle power seat switch is attached to the switch body 33, the knob 34 is disposed so that its reverse side faces the switch body, and so that the wall portions 51 and 52 engage with the projecting shaft 36, the wall portions 54 and 55 with the projecting shaft, and the wall portions 57 58 with the projecting shaft 40. In this state, the knob 34 is pressed toward the switch body. By this pressing, the wall portions 57 and 58 are displaced outward by the projections 40a and 40b, and the projections 40a and 40b are then fitted in the grooves 57a and 58a. At this time, the wall portions 57 and 58 are restored to the original state. Simultaneously, the wall portions 51, 52, 54, and 55 are displaced and restored in the same manner. The knob 34 is thereby prevented from coming off the projecting shafts 36, 38, and 40, that is, it is maintained in the state of being attached to the switch body 33.
In this state, if the knob 34 is moved, for example, to the left as viewed in FIG. 11 by being held by operator fingers, the projecting shaft 38 is pressed leftward as viewed in FIG. 11 by the side wall portion 55 and a switch element incorporated in the switch body 33 is driven through the projecting shaft 38. An unillustrated electrical driving means is thereby operated so that the seat bottom 31 is moved to the left as viewed in FIG. 11, that is, in the direction of the vehicle front. At this time, the projecting shafts 36 and 40 are not moved in the horizontal direction, so that the projection 36 moves relative to the knob 34 between the wall portions 51 and 52, and the projection 40 also moves relatively between the wall portions 57 and 58. When the knob 34 is thereafter released from the operator's hand, the projecting shaft 38 is forced back to the right as viewed in FIG. 11 by a restoring force so as to press the side wall portion 55, and the knob 34 is thereby returned to the neutral position, so that the movement of the seat bottom 31 is stopped. Similarly, if the knob 34 is moved to the right as viewed in FIG. 11, the seat bottom 31 is moved rearward.
If a fore portion of the knob 34 is moved upward, the knob 34 is rotated on the projecting shaft 40 and the projecting shaft 36 is pressed upward by the lower wall portion 52, so that another switch element incorporated in the switch body 33 is thereby driven through the projecting shaft 36. An unillustrated electrical driving means is thereby operated to lift a fore portion of the seat bottom 31. At this time, the projecting shaft 38 is not moved in the vertical direction, but moves relative to the knob 34 between the wall portions 54 and 55. When the knob 34 is thereafter released from the fingers, the projecting shaft 36 is forced back downward by a restoring force so as to press the lower wall portion 52, and the knob 34 is thereby returned to the neutral position, so that the movement of the seat bottom 31 is stopped. During this operation, the projecting shaft 38 does not move forward or rearward; it moves relatively between the wall portions 54 and 55. Similarly, if the fore portion of the knob 34 is moved downward, the fore portion of the seat bottom 31 is moved downward. If a rear portion of the knob 34 is moved in a vertical direction, a rear portion of the seat bottom 31 is moved upward or downward. Further, if the knob 34 as a whole is moved in a vertical direction, the whole seat bottom 31 is moved upward or downward. If an upper portion of the other knob 35 is moved in a longitudinal direction of the vehicle, the knob 35 is rotated on the projecting shaft 42, the projecting shaft 41 is pressed against the side wall portion 59 or 60, and an unillustrated switch element incorporated in the switch body 33 is driven through the projecting shaft 41. An unillustrated electrical driving means is thereby operated to change the inclination of the seat back 32.
In the above-described vehicle power seat switch, the predetermined gaps are provided between the knob 34 and the engagement portions of the switch body 33, i.e., between the projection 40a of the projecting shaft 41 and the groove 57a, between the projection 40b and the groove 58a, between one of the projections of the projecting shaft 38 and the groove 54a, between the other projection of the projecting shaft 38 and the groove 55a, between one of the projections of the projecting shaft 36 and the groove 51a and between the other projection of the projecting shaft 36 and the groove 52a, and the knob 34 is, therefore, not restrained in the neutral position. There is therefore the problem of the knob 34 vibrating to generate noise. A means for solving this problem has been provided which comprises an resilience force application means which is provided between the projecting shafts and the knob to apply a resilience force to the knob to prevent vibrations thereof. However, special parts such as springs are required for the provision of this resilience force application means, resulting in an increase in the total number of parts and, hence, an increase in cost.